Bolt sets an Olympic record with a time of 9.63 seconds. Teammate Yohan Blake takes silver in 9.75, followed by Gatlin in 9.80 and then American teammates Tyson Gay and Ryan Bailey.

Usain Bolt crosses the finish line well ahead of the competition to repeat… (Lee Jin-man / Associated…)

LONDON — Usain Bolt of Jamaica is the world’s fastest man.

Again.

With a huge crowd in the Olympic Stadium roaring and a worldwide audience watching, Bolt blazed through 100 meters in 9.63 seconds, setting an Olympic record as he won his second straight gold medal in the showcase event of the Games.

Putting to rest all the rumors that he was injured after he lost twice to teammate Yohan Blake at the Jamaican Olympic trials, Bolt emphatically outdid a strong and deep field to reach the line first and break the Olympic record of 9.69 he set at Beijing four years ago.

Bolt knelt on the track for a moment before assuming his trademark “Lightning Bolt” pose and waving to the crowd. He and Blake draped Jamaican flags around their shoulders, to the delight of fans from every nation who had been enthralled by his performance.

Blake was second in 9.75 seconds, equaling his personal best. Justin Gatlin of the U.S. was third in a personal-best 9.79, with fellow Americans Tyson Gay fourth in a season-best 9.80 seconds and Ryan Bailey of Long Beach fifth in 9.88 seconds, equaling his personal best.